Various three-dimensional displays for presenting three-dimensional images have been developed (see Patent Document 1, for example.) Generally, a three-dimensional image is presented to a space in front of a screen, a space above the screen or the like in a three-dimensional display.
The three-dimensional display described in Patent Document 1 has a light ray controller having a conic shape. The light ray controller is arranged such that the base of the conic shape is open on a reference plane. A rotation base to which a plurality of scanning projectors are fixed is provided below the reference plane. Each scanning projector irradiates an outer peripheral surface of the light ray controller with a light group including a plurality of light rays from outside of the light ray controller while rotating about a rotation axis on the rotation base. Each light ray emitted by each scanning projector is transmitted by the light ray controller while being diffused in a ridge line direction and is transmitted by the light ray controller while not being diffused in a circumferential direction. Thus, a three-dimensional image is displayed above and inside of the light ray controller having the conic shape.
The light ray group to be emitted by each scanning projector is controlled by a control device such that the three-dimensional image is displayed when observers view above and inside of the light ray controller from a predefined area (viewing area) around the light ray controller.
[Patent Document 1] JP 2011-48273 A